In many medical applications, it is necessary to connect one section of medical tubing, e.g., a catheter, with a device or another catheter. Generally speaking, it is important that these connections be relatively secure and stable so that the catheter does not separate or develop leaks. Security and leak-resistance take on elevated importance in applications where the catheters are implanted within a human body.
One procedure that necessitates implantation of a catheter into the body involves the use of an implantable medical device, e.g., a drug infusion pump. Such implantable medical devices are often used to control pain and/or spasticity, as well as to provide one or more drugs or fluid medications to a particular location within the body. A typical implant procedure may involve implanting a drug infusion pump into a cavity or subcutaneous pocket in the body and delivering a drug, via one or more catheters, to an epidural space or intrathecal space of the spinal column, or to a particular location within the brain.
An exemplary procedure may include positioning a first catheter at the desired location in the body and then connecting the first catheter to a second catheter via a connector. The connection may be made by inserting one end or pin of the connector into a lumen of one catheter and the other end of the connector into the lumen of the other catheter and then sliding both catheters towards one another (towards the middle of the connector). The second catheter may have its opposite end connected to the drug infusion pump. The ends of the pin may have a larger outer diameter than the mating inner diameter of the catheters. To increase the holding/sealing force in these connector configurations, the interference between the pin and the catheter is typically increased. The pin may also incorporate barbs to increase axial holding capacity. While increased interference between the catheter and the pin may improve axial catheter holding force and leak pressure performance, it may also make it more difficult to push the pin into the catheter, especially in a wet surgical environment. Thus, to accommodate desirable catheter attachment forces, axial holding capacity and/or leak performance are sometimes sacrificed.
While adequate, difficulties have been encountered in the manufacture and use of such connectors. For example, one or both of the catheters may incorporate a braid in the catheter wall. The braid may provide various benefits including, for example, increased radial, longitudinal, and torsional stiffness. While these attributes are beneficial, the braid may also limit the expansion capacity of the catheter(s), making it difficult to achieve the desired level of interference. Moreover, even without braided catheters, these connectors, which have been sized to fit within the lumens of the receiving catheters, are small and may be difficult to manipulate by a clinician during implantation (e.g., in a wet, surgical environment). As a result, increasing the interference between the connector and the catheter may not be desirable. Other potential problems may include a lack of ability to adequately secure the catheters relative to the connector; and an inability to provide sufficient strain relief to the catheters. These issues may result in a weakened connection that is susceptible to catheter separation and/or leakage.